Sold at Sotheby's for nearly $9.5 million in 2014, the once-cent magenta is the world's most sought after stamp. In his book The One-Cent Magenta: Inside the Quest to Own the Most Valuable Stamp in the World, New York Times reporter James Barron explores the stamp's history beginning with its printing in the 19th century, and how it came to be coveted within the bizarre, secretive world of high-profile stamp collecting. Jonathan Capehart guest hosted this segment of "The Leonard Lopate Show."